#include<stdio.h>
#include<string.h>

//main 函数有参数吗？
int main(int argc, char* argv[], char* env[])
{
  extern char **environ;
  int i =  0;
  for(;environ[i]; i++)
    printf("%s\n", environ[i]);
  

  //if(argc != 2)
  //{
  //  printf("Usage: %s [-a | -b -c]\n", argv[0]);
  //  return 1;
  //}

  //const char* arg = argv[1];

  //if(strcmp(arg, "-a") == 0)
  //  printf("这是功能1\n");
  //else if(strcmp(arg, "-b") == 0)
  //  printf("这是功能2\n");
  //else if(strcmp(arg, "-c") == 0)
  //  printf("这是功能3\n");
  //else  
  //  printf("Usage: %s [-a | -b -c]\n", argv[0]);




  //for(int i = 0; i < argc; i++)
  //  printf("argv[%d]: %s\n", i, argv[i]);
  
  return 0;
}
